Free ram for widgets with clients previews (#117)

widget/tag_preview.lua

@@ -107,7 +107,7 @@ local function draw_widget(
         end
     end
 
-    return {
+    return wibox.widget {
         {
             {
                 {
@@ -182,8 +182,7 @@ local enable = function(opts)
 
         tag_preview_box.maximum_width = scale * geo.width + margin * 2
         tag_preview_box.maximum_height = scale * geo.height + margin * 2
-        tag_preview_box:setup(
-            draw_widget(
+        tag_preview_box.widget = draw_widget(
             t,
             tag_preview_image,
             scale,
@@ -199,7 +198,6 @@ local enable = function(opts)
             geo,
             margin
         )
-        )
     end)
 
     awesome.connect_signal("bling::tag_preview::visibility", function(s, v)
@@ -208,6 +206,11 @@ local enable = function(opts)
             tag_preview_box.y = s.geometry.y + widget_y
         end
 
+        if v == false then
+            tag_preview_box.widget = nil
+            collectgarbage("collect")
+        end
+
         tag_preview_box.visible = v
     end)
 end

widget/task_preview.lua

@@ -153,6 +153,9 @@ local enable = function(opts)
                 widget_width,
                 widget_height
             )
+        else
+            task_preview_box.widget = nil
+            collectgarbage("collect")
         end
 
         if not placement_fn then

widget/window_switcher.lua

@@ -59,6 +59,8 @@ local window_switcher_hide = function(window_switcher_box)
     -- Stop and hide window_switcher
     awful.keygrabber.stop(window_switcher_grabber)
     window_switcher_box.visible = false
+    window_switcher_box.widget = nil
+    collectgarbage("collect")
 end
 
 local function draw_widget(